docs: def _rel_import(module, tgt):
      """Using relative import in both Python 2 and Python 3"""
      try:
          exec("from ." + module + " import " + tgt, globals(), locals())
      except SyntaxError:
          # On Python < 2.5 relative import cause syntax error
          exec("from " + module + " import " + tgt, globals(), locals())
      except (ValueError, SystemError):
          # relative import in non-package, try absolute
          exec("from " + module + " import " + tgt, globals(), locals())
      return eval(tgt)